Atlas / MCP servers / nspady / Google Calendar MCP Server

Google Calendar MCP ServerBLOCK

Name: Google Calendar MCP Server
Author: nspady

mcp/nspady/google-calendar-mcp

MCP server by nspady · Audited 2026-10-12

⚑ Report / re-scan Source ↗

MCP integration for Google Calendar to manage events.

Verdict

BLOCK

Grade

Trust score

69 /100

Exposed tools

13 9r · 3w · 1d

Transport

stdio · streamable-http

License

MIT

Stars

1,200

Overview

From the repository's own README, as read at the audited commit. Badges and raw HTML are left out.

A Model Context Protocol (MCP) server that provides Google Calendar integration for AI assistants like Claude.

I also built Cocal, the calendar integration I wanted for chat: a visual calendar inside Claude that shows your whole day around a proposed time, plus booking links and invites you manage from the conversation. It's hosted, so it works on desktop and mobile with no Google Cloud setup.

Real Cocal UI with sample calendar data. Click either screenshot to enlarge. Try Cocal →

Features

Multi-Account Support: Connect multiple Google accounts (e.g., work, personal) and query them simultaneously
Multi-Calendar Support: List events from multiple calendars in a single request
Cross-Account Conflicts: Detect overlapping events across any combination of calendars
Event Management: Create, update, delete, and search calendar events
Recurring Events: Advanced modification capabilities for recurring events
Free/Busy Queries: Check availability across calendars
Smart Scheduling: Natural language understan

Read from source at commit 62203eb4d7d7OBSERVED · 2026-10-12

Connect

Built from this server's own package name, version and transport as found in its source — not copied from anyone's documentation, so it cannot drift against a page we do not control. Replace the environment placeholders with a token scoped to the least it needs.

claude-code

claude mcp add google-calendar-mcp --env CLAUDE_API_KEY=${CLAUDE_API_KEY} --env GOOGLE_APPLICATION_CREDENTIALS=${GOOGLE_APPLICATION_CREDENTIALS} --env GOOGLE_CALENDAR_MCP_TOKEN_PATH=${GOOGLE_CALENDAR_MCP_TOKEN_PATH} --env GOOGLE_OAUTH_CREDENTIALS=${GOOGLE_OAUTH_CREDENTIALS} -- npx -y @cocal/[email protected]

claude-desktop

{
  "mcpServers": {
    "google-calendar-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@cocal/[email protected]"
      ],
      "env": {
        "CLAUDE_API_KEY": "${CLAUDE_API_KEY}",
        "GOOGLE_APPLICATION_CREDENTIALS": "${GOOGLE_APPLICATION_CREDENTIALS}",
        "GOOGLE_CALENDAR_MCP_TOKEN_PATH": "${GOOGLE_CALENDAR_MCP_TOKEN_PATH}",
        "GOOGLE_OAUTH_CREDENTIALS": "${GOOGLE_OAUTH_CREDENTIALS}"
      }
    }
  }
}

Exposed tools (13)

9 read · 3 write · 1 destructive. Blast radius: 1 tool can delete or overwrite — an agent that can be talked into calling a tool can be talked into calling this one.

Tool	Risk	Description
`create-event`	write	Create a new calendar event. eventLabelId (custom color) takes precedence over the legacy colorId.
`create-events`	write	Create multiple calendar events in bulk. Accepts shared defaults (account, calendarId, timeZone) that apply to all events, with per-event overrides. Skips conflict and duplicate detection for speed.
`delete-event`	destructive	Delete a calendar event.
`get-current-time`	read	Get the current date and time. Call this FIRST before creating, updating, or searching for events to ensure you have accurate date context for scheduling.
`get-event`	read	Get details of a specific event by ID.
`get-freebusy`	read	Query free/busy information for calendars. Note: Time range is limited to a maximum of 3 months between timeMin and timeMax.
`list-calendars`	read	List all available calendars
`list-colors`	read	List available legacy color IDs for calendar events. Pass calendarId to also get that calendar
`list-events`	read	List events from one or more calendars. Supports both calendar IDs and calendar names.
`manage-accounts`	read
`respond-to-event`	read	Respond to a calendar event invitation with Accept, Decline, Maybe (Tentative), or No Response.
`search-events`	read	Search for events in a calendar by text query.
`update-event`	write	Update an existing calendar event with recurring event modification scope support. eventLabelId (custom color) takes precedence over the legacy colorId.

Trust audit

BLOCKgrade D · trust 69/100 Do not install this without reading the findings. The audit found something that could harm you or your machine.

Layer	What it checks	Result
L0	Provenance & inventory	PASS
L1	Static analysis of the code	FAIL
L2	Instruction surface (what it tells the agent)	PASS
L3	Class-specific surface	WARN
L4	Behavioural (sandbox)	SKIPPED

What the source does

Filesystem: declared (6 observation(s))
Network: declared (3 observation(s))
Shell: none-observed
Dependencies: not all pinned
Secrets in source: found

Findings (22)

HIGHSupply chain · supply.typosquat · CWE-829, CWE-1357

package.json

gaxios ~ axios

Why it matters. dependency name one edit from a popular package

Fix. verify the package; likely typosquat

MEDIUMNetwork egress · net.beacon_words · CWE-200, CWE-319

src/handlers/core/ManageAccountsHandler.ts:244

callback_url: started.callbackUrl!,

MEDIUMNetwork egress · net.beacon_words · CWE-200, CWE-319

src/types/structured-responses.ts:435

callback_url?: string;

MEDIUMHard-coded secrets · secret.private_key · CWE-798, CWE-321

src/tests/unit/auth/serviceAccount.test.ts:31

'-----BEGIN PRIVATE KEY-----',

MEDIUMFilesystem / path · mcp.destructive_tools · CWE-22, CWE-59

delete-event

Why it matters. 1 tool(s) can delete or overwrite

Fix. prefer a read-only mode or scoped tokens; the page states the blast radius

LOWInventory / provenance · inv.hidden_file · CWE-1104

.cursorignore

.cursorignore

Why it matters. hidden member outside the usual dotfiles

Fix. review its purpose

LOWInventory / provenance · inv.hidden_file · CWE-1104

.release-please-manifest.json

.release-please-manifest.json

Why it matters. hidden member outside the usual dotfiles

Fix. review its purpose

LOWInformation disclosure · disclose.log_secret · CWE-209, CWE-532

src/tests/unit/schemas/tool-description-analysis.test.ts:243

console.log(`\nTotal token count: ${analysisReport.totalTokens.toLocaleString()}`);

LOWFilesystem / path · fs.traversal · CWE-22, CWE-59

src/handlers/core/BaseToolHandler.ts:5

import { getCredentialsProjectId } from "../../auth/utils.js";

LOWFilesystem / path · fs.traversal · CWE-22, CWE-59

src/handlers/core/BaseToolHandler.ts:6

import { CalendarRegistry } from "../../services/CalendarRegistry.js";

LOWFilesystem / path · fs.traversal · CWE-22, CWE-59

src/handlers/core/BaseToolHandler.ts:7

import { validateAccountId } from "../../auth/paths.js";

LOWFilesystem / path · fs.traversal · CWE-22, CWE-59

src/handlers/core/BaseToolHandler.ts:8

import { convertToRFC3339 } from "../../utils/datetime.js";

LOWFilesystem / path · fs.traversal · CWE-22, CWE-59

src/handlers/core/BaseToolHandler.ts:9

import { isCalendarNotAccessibleError } from "../../utils/google-api-errors.js";

LOWNetwork egress · net.beacon_words · CWE-200, CWE-319

src/tests/unit/handlers/ManageAccountsHandler.test.ts:219

expect(response.callback_url).toContain('oauth2callback');